Flu season has been especially hard on younger people this year compared to past years and the CDC is still urging people to go out and get vaccinated.

According to CNN, the Centers for Disease Control and Prevention (CDC) accounted Thursday the flu is also killing more people under 65 than usual. People aged 18-64 account for 61 percent of influenza hospitalizations, compared to 35 percent for that age range in past years.

People aged 25-64 have also accounted for more than half of all flu-related deaths. The CDC estimated that only a third of the large group of 18-64-year-olds had been vaccinated. Since flu season may not end until early spring, it is still not too late to get vaccinated.

"Influenza can make anyone very sick, very fast and it can kill," CDC director, Dr. Tom Frieden told CNN. "Vaccination every season is the single most important thing you can do to protect yourself."

He said that while experts need to continually develop vaccines for new strains of the flu, the current ones are still better than not being vaccinated at all.

"We are committed to the development of better flu vaccines, but existing flu vaccines are the best preventive tool available now," Frieden said.

According to the latest CDC weekly influenza report, 24 states still reported widespread flu activity, meaning at least half of the state's geographic regions are reporting that way.

"I want to remind you that the season is not over," Dr. Anne Schuchat, director of the National Center for Immunization and Respiratory Diseases, told CNN. "There is still a lot of influenza circulating. If you haven't been vaccinated yet, it's not too late for you to benefit."

Hospitalizations are the primary way for the CDC to report the current flu season's severity, the Associated Press reported. Just as the 2009 swine flu pandemic made a lot of young people sick, H1N1 has been the leading cause of flu hospitalizations.

The CDC said the virus has not mutated but is finding people who have not been infected with it and who have not been vaccinated.